A man holds bundled of khat (qat), a stimulant plant that is illegal in the US. Photograph: Justin Tallis /AFP /Getthy

Seventeen people have been charged with running an international khat dealing operation that allegedly made hundreds of thousands of dollars by shipping several tons of the plant, a stimulant illegal in some countries, to the US.

The group is accused of importing African khat into Manhattan for sale on the streets of New York and Massachusetts, in packages sent from overseas by its alleged British-based leader.

Yadeta Bekri, a 23-year-old man operating from England, is facing a potential life prison sentence in the US after being charged with trafficking large quantities of the plant that were obtained from Yemen, Kenya and Ethiopia.

Bekri is accused of sending the packages via UPS from Britain, China, Holland and Belgium for collection by a pair of colleagues, who then distributed the khat for sale, before sending the proceeds back to Bekri via his fiancee in Minnesota.

Bekri was indicted in New York on Friday on charges of “operating as a major trafficker,” a felony carrying a potential life sentence; money laundering; and possessing and selling illegal drugs. The other 16 members of what prosecutors described as a “global khat trafficking ring” were indicted on charges including money laundering and possessing and selling khat.

Eric Schneiderman, New York’s attorney general, said in a statement that “a sophisticated operation accused of bringing drugs into the United States and sending the profits overseas has been shut down”. Describing khat as a “dangerous and illegal drug,” Schneiderman added: “Trafficking often funds other criminal activity”.

Bill Bratton, the commissioner of the NYPD, said in a statement that the alleged dealing operation showed that “illegal drugs can find their way into our city from any corner of the world via organised criminal networks”.

The plant, which is cultivated largely in eastern Africa, contains stimulants that are released when its stems and leaves are chewed. It has long been popular among some communities of Somali, Yemeni and Ethiopian descent. However, it is illegal in the US and became a banned class C drug in Britain on Tuesday. It contains cathinone, which is a Schedule I controlled substance in New York, and cathine, a schedule IV controlled substance.

Theresa May, the British home secretary, introduced the ban against the advice of her official advisory committee on the misuse of drugs. The ban was also criticised last year by the home affairs committee of MPs, which warned it would create tensions between police and immigrant communities and was not based on evidence that using khat caused medical or social harm.

According to a 215-count indictment unsealed by New York prosecutors on Friday, Bekri – who was allegedly known to his co-conspirators as Murad – obtained large quantities of khat from Ethiopia, Kenya and Yemen, and shipped it to the US from Britain, China, Holland and Belgium.

Prosecutors allege that his two New York “managers”, Bayan Yusuf and Ahmed Adem, collected the packages from UPS stores and sold the khat on to customers and dealers in Brooklyn, Rochester and Buffalo in New York, and in Everett, Massachusetts.

Yusuf and Adem are accused of delivering tens of thousands of dollars in cash collected from khat sales by car to Ibsitu Hashi, Bekri’s fiancee, who was based in Minnesota. She then wired money back to Bekri in England via Dubai, the prosecutors said.

Prosecutors said on Friday that the dealers were placed under surveillance as part of a nearly year-long investigation by state and local law enforcement agents led by Schneiderman’s organised crime task force and the New York police department’s intelligence division.

The indictment details a series of apparently intercepted telephone calls and text messages between the defendants, in which they allegedly organised khat sales and revenues while also “using codes and speaking in a guarded, cryptic manner”. They allegedly discussed transporting cash in amounts of up to $143,000.

Two defendants were “observed on several occasions via electronic surveillance” bringing several 25-pound boxes of khat into the Islamic Society of Flatbush in Brooklyn, the prosecutors said, while others were watched using rental storage facilities in Brooklyn and Queens.

Prosecutors said that Bekri was based in England but did not offer more specifics. Lawyers for Bekri and his co-defendants could not immediately be reached on Friday. “The charges against the defendants are accusations and the defendants are presumed innocent until and unless proven guilty in a court of law,” Schneiderman’s statement said.